Gas-Fired Portable Unvented Infrared Heater

ABSTRACT

A portable radiant heater supplied by an associated fuel source comprises a housing having a handle for transporting the heater. A plenum in the housing receives fuel from the associated fuel source and mixes the fuel with air. A burner assembly includes a radiant surface that communicates with the plenum. A regulator limits the pressure of the associated propane source to approximately eleven inches water column, and an oxygen depletion system associated with the burner assembly automatically shuts off the heater at a predetermined oxygen content. A tank fitting with a position that can be adjusted relative to the regulator facilitates the installation of the associated fuel source to the heater.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application in a continuation-in-part of and claims the benefit ofU.S. Utility patent application Ser. No. 12/441,462, filed on Mar. 16,2009, which claims priority from PCT Patent Application No.PCT/US07/07426, filed on Mar. 26, 2007, which claims priority from U.S.Provisional Application No. 60/743,757, filed on Mar. 24, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to improved portable heaters used inrelatively small enclosures. More particularly, the invention relates toa uniquely configured propane source infrared heater for use inenclosures such as small recreational enclosures, temporary workenclosures, or vehicles. Although the invention was designed for indoorareas, it will be appreciated that it has broader applications and maybe advantageously employed in a wide variety of environments withoutdeparting from the scope of the invention.

2. Description of Related Art

Gas-fired portable heaters are well known in the art and are used inmultiple environments. The heater typically includes a housing having achamber. The housing has an inlet for receiving air into the chamber.Gas is introduced into the chamber to be mixed with the air in order tocomplete combustion and provide an infrared heating surface. A plenumdirects the heat toward a mesh screen and evenly distributes it over thesurface thereof. The overall goal in designing such a unit is to achievea radiant surface that provides even, stable heating over the entiresurface.

The use of such heaters is strictly regulated for outdoor only use dueto the emission of carbon monoxide. Prior designs in existing portableunits are subject to a wide variety of problems. Most importantly, theprior designs are not safe or certified to operate in small recreationalenclosures such as tents, truck-caps, fishing huts, trailers, vans, etc.There are a few reasons why the devices found in the prior art are notadequate to perform in such environments. First, the portable heatersthat exist today operate at a high pressure generally on the order of 12psi. Specifically, the pressure from the propane tank through aregulator is necessarily high in order to achieve adequate gas and airflow. In addition to requiring high pressure, previous designs do nothave the ability to pass strict combustion requirements at a high andlow firing condition and at a reduced pressure. For example, a newstandard developed for this product (CSA International 4.98 US) statesthat “the appliance shall not produce carbon monoxide in excess of 0.010(100 ppm) percent in a room with no air changes occurring duringcombustion of the amount of gas necessary to reduce the oxygen contentof the room to 18 percent by volume.” In addition, they do not possessan oxygen depletion system (“ODS”) (Capreci/Part No. 21500). Theseshortcomings have prevented the portable heaters found in the prior artfrom adequately performing in small recreational and temporary workenclosures.

Existing portable units typically combust a fuel such as propane togenerate heat. Propane tanks come in a variety of sizes such as a 1pound tank that can be replaced when the propane fuel is fully consumed.To replace an empty propane tank with a full propane tank, existingheaters require the propane tank to be raised into the connection pointof the heater in an upward direction from below to avoid contacting aprotective structure that guards the connection between the fuel tankand the heater. In close quarters, this can be difficult to accomplish.As an alternative, the heater can be lifted to facilitate thereplacement of an empty propane tank with a new tank. However, liftingthe heater to install a replacement propane tank can be cumbersome, anddifficult to do with one person.

Attempts have been made to alleviate at least some of the burdensassociated with replacing an empty propane tank. Such attempts havetypically revolved around a rotatable regulator that can be rotated inorder to expose the connection point to establish a direct connectionbetween the propane tank and the regulator. However, repeated rotationof the regulator can subject the regulator to damage from prolonged use,which in turn can cause an undesirable connection between the heater andthe propane tank and hamper the ability of the heater to functionproperly.

Therefore, a need exists to provide a portable infrared heater capableof performing safely in small recreational enclosures and temporary workenclosures that can facilitate ready replacement of a fuel source.

BRIEF SUMMARY OF THE INVENTION

This invention contemplates a new and improved burner assembly that iscapable of performing safely in small recreational facilities such astents, truck-caps, vans, fishing huts, trailers, etc.

According to the present invention, a portable heater includes an outerhousing having a first or front face, a second or rear face, and twosides interconnecting the front and rear faces. An air inlet is locatedon the front face of the housing, preferably along a lower portionthereof. A gas supply or tank is partially enclosed and supported by theouter housing. The gas supply or tank is optionally connected with aswivel connector for ease in replacing the supply, and a stationaryregulatory within the heater housing decreases the pressure of thesupply. A burner venturi, having a cylindrical body extending upwardlyat a slight angle, is disposed within the housing. The burner venturialso has a mouth operatively associated with a bottom end of thecylindrical body. Gas is released from the gas supply into the mouth ofthe burner venturi. At the same time, air is drawn into the mouth of theburner venturi from the air inlet. The air and gas mix thoroughly asthey travel upwardly through the burner venturi.

Upon exiting the burner venturi, a baffle directs the air/gas mixtureinto a plenum to further mix, enter a rear face of a radiant surface,and then ignited on a top surface where combustion occurs. Anyconventional means for initially sparking or igniting the air/gasmixture at the burner surface can be used. The burner plenum is heatedto an elevated temperature and the radiant surface emits heat to theambient environment. Combustion products are directed off a deflectorshield which reduces the temperature of the products before exiting anoutlet at an upper portion of the housing.

The air inlet of the present invention is advantageously designed toprovide air flow along the hot burner plenum resulting in an increasedvelocity of air flow to the burner venturi. As the burner venturi isheated, the thermal properties result in the air/gas mixture passingupwardly through the angled burner venturi creating a chimney typeeffect. The chimney effect created by the present invention increasesthe air flow velocity into the burner venturi. In addition, the devicereduces pressure from the gas supply and has the ability to satisfycombustion requirements at low fire condition.

This improved invention uses a single regulator in conjunction with twoswivel connectors, preferably with check valves therein. These and otherobjects of the present invention will become more readily apparent froma reading of the following detailed description taken in conjunctionwith the accompanying drawings wherein like reference numerals indicatesimilar parts, and with further reference to the appended claims.

According to one aspect, the present invention provides a portableradiant heater supplied by an associated fuel source. The heatercomprises a housing having a handle for transporting the heater and aplenum in the housing receives fuel from the associated fuel source andmixes the fuel with air. A burner assembly includes a radiant surfacethat communicates with the plenum. A regulator limits the pressure ofthe associated propane source to approximately eleven inches watercolumn, and an oxygen depletion system associated with the burnerassembly automatically shuts off the heater at a predetermined oxygencontent. A tank fitting with a position that can be adjusted relative tothe regulator facilitates the installation of the associated fuel sourceto the heater.

According to another aspect, the present invention provides a portableradiant heater including a regulator that is coupled to the heater at afixed position relative to the housing. The tank fitting is optionallypivotally coupled to a bracket to pivot about a transverse axis relativeto the bracket, which is itself coupled to the housing. The portableradiant heater can further include a fitting nut that is stationaryrelative to the housing to which a fuel-carrying conduit is coupled toestablish fluid communication between the pivotal tank fitting and theregulator. The bracket can optionally be slidable along a track to beselectively withdrawn from, and introduced into the housing for exposingthe tank fitting externally of the housing and facilitating installationof the associated fuel source. The fuel-carrying conduit can be aflexible fuel hose to allow the position of the slidable bracket to beadjusted during installation of the associated fuel source.

According to yet another aspect, the present invention provides aportable radiant heater comprising a plurality of tank fittings, eachwith a position that can be adjusted relative to the regulator tofacilitate the installation of a plurality of associated fuel sources tothe heater. At least one tank fitting can optionally be disposedadjacent to each lateral side of the heater and the regulator isseparated approximately equidistantly from the at least one tank fittingadjacent to each lateral side. Optionally, the regulator is stationaryrelative to the housing and each tank fitting can be adjusted relativeto the housing of the heater. Each tank fitting can also be pivotallycoupled to the housing to pivot about a transverse axis relative to thehousing to facilitate installation of the associated fuel source. Forexample, each tank fitting can be pivotally coupled to a door that canbe adjusted to a closed position to conceal the associated fuel sourceto pivot about a transverse axis relative to the door.

According to yet another aspect, the present invention provides aportable radiant heater including a tank fitting that is releasablycoupled to the heater by a releasable bracket. The releasable tankfitting can be removed from the releasable bracket while remainingcoupled to a flexible fuel line that transports fuel from the associatedfuel source to be delivered to the regulator.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangement ofparts, embodiments of which will be described in detail in thisspecification and illustrated in the accompanying drawings which form apart hereof, and wherein:

FIG. 1 is a perspective cross-sectional view of a heater assembly inaccordance with an embodiment of the present invention;

FIG. 2 is a longitudinal cross-sectional view of the heater assembly inaccordance with an embodiment of the present invention;

FIG. 3 is an enlarged elevational view of a thermocouple, spark igniter,and pilot tube assembly used in an embodiment of the present invention;

FIG. 4 is a perspective view of the heater taken generally from thefront and left hand side;

FIG. 5 is a perspective view of the heater taken generally from thefront and right hand side;

FIG. 6 is a perspective view of the heater taken generally from the rearand right hand side;

FIG. 7 is a perspective view of the heater taken generally from the rearand left hand side;

FIG. 8 is a perspective elevational view of the heater in accordancewith an embodiment of the present invention;

FIG. 9 is a bottom view of a portable heater in accordance with anembodiment of the present invention;

FIG. 10 is a side elevational view of a portable heater in accordancewith an embodiment of the present invention;

FIG. 11 is a side elevational view of a portable heater in accordancewith an embodiment of the present invention;

FIG. 12 is a rear elevational view of a portable heater in accordancewith an embodiment of the present invention;

FIG. 13 is a front elevational view of a portable heater in accordancewith an embodiment of the present invention;

FIG. 14 is a top view of a portable heater in accordance with anembodiment of the present invention;

FIG. 15 is a side elevational view of a portable heater in accordancewith an embodiment of the present invention showing a fully enclosedfuel source that can be exposed by opening of a hinged door;

FIG. 16 is front elevational view of a portable heater in accordancewith an embodiment of the present invention showing an attached batterypack for use with an optional fan to increase circulation;

FIG. 17 is a top perspective view of a portable heater in accordancewith an embodiment of the present invention with a top handle removedshowing an optional rear fan in the housing operated by removable andoptionally rechargeable dry cell batteries;

FIG. 18 is a rear elevational view of a portable heater in accordancewith an embodiment of the present invention showing a detachable doorfor enclosing a fuel source;

FIG. 19 is a rear elevational view of a portable heater in accordancewith an embodiment of the present invention with the detachable doorshown in FIG. 18 removed to illustrate a fuel source that is pivotableabout a fuel supply connection;

FIG. 20 is a top elevational view of a portable heater in accordancewith an embodiment of the present invention with a handle and frontgrill removed to show two fuel sources positioned about one side of theheater;

FIG. 21 is a front elevational view of a portable heater of FIG. 20showing a front fuel source in ghost lines;

FIG. 22 is a top elevational view of an embodiment of a heater accordingto the present invention illustrating two fuel sources positioned aboutopposed sides of the heater;

FIG. 23 is a front elevational view of the embodiment shown in FIG. 22illustrating the fuel sources enclosed within a slotted enclosure;

FIG. 24 is a top elevational view of an embodiment of a heater accordingto the present invention with handle and front grill removedillustrating two fuel sources positioned at the rear of the heater andpartially protruding through the rear wall of the heater;

FIG. 25 is a front elevational view of the embodiment shown in FIG. 24;

FIG. 26 is a rear perspective view of an embodiment of a heateraccording to the present invention with rear and side panels removed toillustrate pivotable fuel source rotation and inline regulator;

FIG. 27 is a bottom perspective view of an embodiment of an optionalremote LP gas supply hose in a coiled configuration;

FIG. 28 is a side perspective view illustrating an embodiment of therotatable connection and bracket for an LP gas supply;

FIG. 29 is another side perspective view illustrating an embodiment ofthe rotatable connection and bracket of FIG. 28;

FIG. 30 is a front elevational view illustrating an embodiment of therotatable connection and bracket of the LP gas supply, wherein said LPgas supply is shown in ghost lines;

FIG. 31 is a side elevational view illustrating the rotatable connectionof FIG. 28;

FIG. 32 is a top elevational view illustrating the rotatable connectionof FIG. 28;

FIG. 33 is a bottom elevational view illustrating the rotatableconnection of FIG. 28;

FIG. 34 is a side perspective view of an embodiment of a heater usingthe rotatable connection of a LP gas supply with top and side coversremoved;

FIG. 35 is a side perspective view of an embodiment of a heaterincluding an attachment mechanism for receiving two fuel sourcesillustrating a sliding track arrangement for the fuel source connectionin conjunction with a flexible braided hose, the heater housing havingthe enclosing shroud or enclosure removed;

FIG. 36 is a side perspective view of an embodiment of a portion of aportable heater illustrating a fixed fuel regular positioned within apivotal door of the housing in conjunction with a flexible braided hose;

FIG. 37 is a side perspective view of an embodiment of the attachmentfor the fuel source illustrating a movable fuel tank fitting attached bya flexible house with a clip arrangement within the housing for cylinderpositioning and retention;

FIG. 38 is a side perspective view of an embodiment of a fuel sourceconnection illustrating a pivotal weighted clip;

FIG. 39 is an enlarged side perspective view of the rotating clip ofFIG. 38;

FIGS. 40 through 44 are perspective and other views of a warming trayutilized in association with the heater disclosed herein.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention. Relative language usedherein is best understood with reference to the drawings, in which likenumerals are used to identify like or similar items. Further, in thedrawings, certain features may be shown in somewhat schematic form.

The Figures show a portable heater for use in confined spaces withvarious configurations for the positioning of the fuel source(s).Referring now to the drawings wherein the showings are for purposes ofillustrating the preferred embodiment of the invention only, and not forpurposes of limiting same, the Figures show a portable heating device Aadapted for use in small enclosed environments. Although the presentinvention is designed for use in recreational enclosures and temporarywork enclosures, it will be appreciated that other uses arecontemplated.

The portable heater A includes a housing 10 having a front face 12, arear face 14, and two sides 16, 18. The housing 10 is preferablymanufactured to have smooth contours to prevent snagging or catching ofthings such as clothing, fabric, etc. A stepped recess or externalcavity is formed in an upper front corner region of the left side 16 ofthe housing 10 for supporting a control knob or temperature controller20. The recess provides protection against inadvertent contact andaccidental changing of the temperature. The temperature controller 20preferably has four positions: off, pilot, low, and high (not shown)although continuously variable positions for infinitely variable heatingis also contemplated within the scope of this invention. Controller mayincorporate a piezo spark igniter integral to controller stem rotation.

Another recess is disposed on the upper back corner of the left side 16of the housing 10. This recess supports an igniter button 22 foractivating the heater A. This recess also protects against inadvertentcontact with the igniter button 22.

The heater A is supported by two elongated legs 24 a, 24 b laterallydisposed along the outboard edges of the rear face 14 and front face 12respectively. The legs 24 a, 24 b are preferably grooved providing afriction surface to contact the supporting surface and preferably extendover the entire width of the housing to provide a wide “footprint” andstable support area for the heater. In another embodiment (not shown),additional legs extending front to rear are provided beneath legs 24 a,24 b to increase air flow beneath the heater. Further embodimentsforesee alternative leg arrangements, such as a vertically extending legon each of the four corners of the base of the heater, or a legextending front to rear on either side of the base of the heater. Ahandle 26 is recessed from and extends from the top of the heater at anangle directed away (approximately)15° from the front face 12. Theoffset allows the handle to remain cool for handling by a user while theangled orientation of the handle 26 protects the user's hand from heatexiting the top of the heater while the user transports the heater. Thehandle 26 is optionally grooved providing an enhanced gripping surfacefor the user.

A shield or metal grid 30 is attached to the front face 12 of the heaterto provide protection to the heater components. In addition, the shieldprevents accidental contact with the hot portions of the heater frontface 12. The shield is preferably made from elongated wire metal stripsand peripheral pieces are received in openings 32 in the housing tosecure the shield to the heater. In addition, only one screw (not shown)need be removed for access to the interior components enabling easyservicing or replacement of selected components of the heater. Twokeyhole openings or recesses 34 a, 34 b are located on the upper portionof the back face 14 of the heater allowing the user to hang the heaterin an elevated position.

An opening or air inlet 40 is disposed on a lower portion of the frontface 12 of the heater for receiving and filtering air drawn into thehousing. The air inlet 40 is preferably formed from a series ofelongated slits 42 equispaced across the housing beneath the shield.However, any opening that adequately provides air inflow is within thescope of the present invention.

An LP (“Liquified Petroleum” or “Liquified Propane”) gas supply tank 50is secured to and partially enclosed by the housing 10 (See FIGS. 5 and6). The LP gas supply 50 is preferably a removable canister or propanetank that can be replaced by a new tank or removed, refilled, andre-installed in the housing. A conical dome 52 protrudes from the side18 of the housing 10 and partially encloses the gas supply tank 50. Thedome acts as a protective shroud to cover the interconnection of thetank with the housing. For example, a one pound propane cylinder may beconnected to the housing to provide approximately six hours ofcontinuous operation on the low setting. Alternatively, the heater canbe supplied, for example, by a conventional twenty pound propane tankhaving an extended length hose assembly so that the tank can be locatedaway from the heated region. For instance, the propane tank can bepositioned outside a tent, cabin, fishing shanty garage, etc. while theheater is located within the structure and the heater provide on theorder of one hundred and ten hours of heat with the larger gas supplytank.

The gas supply 50 is connected through fittings and lines to a regulatorwhich connects to a valve and orifice 56 (See FIG. 1) which isselectively adjustable between open and closed positions, access beingprovided to the gas supply fitting through window opening 58 for remoteLP gas supply hose tightening and leak checking (see FIG. 6). Optionallythe LP gas supply hose 130 with connector fittings 132, 134 is storedunderneath the unit within receptacles 136 in combination with sideledges 138 illustrated in FIG. 27. It is recognized that the LPcouplings may be “quick connects” when the supply pressure is alreadyregulated to about 11″ water column. In this embodiment, thequick-coupler hose is integral to the heater and downstream from heaterregulator(s) but before the control valve to facilitate connection to aregulated hose supply from an external fuel source such as a 20 poundcylinder. Similarly, the regulated fuel supply (11″ water column) couldoriginate from a self-contained system as in a recreational vehicle. Thequick-coupler hose connection would incorporate positive fuel shut-offin both male and female connection components to prevent fuel escapewhen disconnected.

Referring again to FIGS. 1 and 2, a burner venturi 60 is enclosed withinthe housing 10 and operates to mix oxygen and propane for combustion.The burner venturi 60 has a hollow generally cylindrical body 62 and atapered mouth 64 having a wider diameter than the body 62. The burnerventuri is disposed at an angle a relative to the longitudinal axis ofthe heater A. The mouth 64 of the burner venturi is positioned onapproximately the same axial plane as the air inlet 40 and thecylindrical body 62 extends upwardly from the mouth 64. The orifice 56which is attached to the gas supply 50 is located directly beneath themouth 64 of the burner venturi 60.

Also located within the housing 10 is a generally planar radiant surface70 disposed at an angle a relative to the longitudinal axis of theheater. A rear face of the radiant surface is in communication with acavity or plenum chamber 72. The burner plenum receives the air/gasmixture from the venturi and distributes the mixture over and throughthe rear face of the radiant surface. Thus, in operation, the orifice56, attached to the gas supply, is opened releasing a fuel gas such aspropane into the mouth 64 of the burner venturi 60. Associated with theorifice is a regulator that reduces the delivery pressure of the fuelgas from the tank (rated up to 150 psi) to eleven inches of water columnin one stage. Thus, this portable heater operates at a significantlylower pressure than existing commercially available units. The stream ofgas exiting the orifice 56 creates a vacuum effect drawing air from theair inlet 40 into the mouth 64 of the burner venturi. Propane and airare thoroughly mixed in the burner venturi 60 and plenum 72 in order toachieve complete combustion and produce a clean burning infrared heatingsurface. The mixture of oxygen and propane travels upward through thecylindrical body 62 of the burner venturi 60 until reaching the plenumchamber 72. To prevent the mixture of propane and oxygen fromimmediately exiting the plenum chamber 72, a solid baffle 76 is providedwhich forces the air/gas mixture downward into communication with therear face of the radiant surface.

The radiant surface may be a burner tile or a multi-ply screens (notshown) that define a plurality of small openings which permit combustionof the air/gas mixture as it passes therethrough. A means is providedfor initially sparking or igniting the mixture at the radiant surface.In the present invention a container 80 houses the pilot 82 and theigniter 84 (see FIG. 3) which provides the initial sparking. It will beappreciated that any conventional means for initially sparking origniting the mixture can be utilized. Combustion of the air/gas mixtureis maintained and reaches elevated temperatures of approximately 1200°F. The heater shown in the drawings with one propane cylinder is ratedat a minimum 4000 BTUs and a maximum 9000 BTUs at eleven inches watercolumn pressure. Other ratings are also potential alternatives,including up to 20,000 to 25,000 BTU models when more than one propanecylinder and associated burner assemblies are utilized.

A reflector 90 extends outwardly from the top of the burner plenum 72 atan angle directed toward the top portion of the front face 12 of thehousing 10. The natural convective upward path of the combustionproducts leads the combustion products into contact with the reflector90. The reflector 90, in addition to directing the radiant energy outputfrom the heater toward the front surface of the housing, also acts as adeflector and reduces the temperature of the combustion products exitingthe heater which greatly reduces the chance for ignition of acombustible material if it comes into contact with the heater A. Anoutlet 92 is disposed near the top of the housing 10 allowing warm airto mix with combustion products and exit the device after contacting thereflector 90. In addition, a deflector 95 is disposed on the top offront face 12 which reduces the temperature of the combustion productsexiting the heater which greatly reduces the chance for ignition of acombustible material if it comes into contact with the heater A.

In addition, there is an outlet or grate 94 disposed rearward of outlet92 that communicates with the interior of the housing. It provides acontinuous flow path for air (that does not enter the venturi) to flowfrom the inlet 40 around the rear of the plenum chamber and exit thehousing rearward of the deflector. This enhances the chimney effect asdescribed above since a large amount of ambient air is drawn into thehousing, a portion used for combustion purposes and the remainderconvects upwardly along the rear of the plenum and the deflector to exitvia the openings 94. The air inlet 40 of the present invention isdesigned to encourage air flow along the back of the hot burner plenum72, advantageously resulting in an increased velocity of air flow to theburner venturi, as well as cooling the rear housing 10. As the burnerventuri 60 is heated, the thermal convection properties urge the air/gasmixture through the upwardly angled burner venturi 60 creating a chimneytype effect. The chimney effect created by the present inventionincreases the fresh air flow velocity into the burner venturi, enablingthe pressure from the gas supply 50 to be reduced, yet burn efficientlyon high or low settings.

In addition to housing the pilot 82 and the igniter 84, the container 80preferably houses an oxygen depletion system (See FIG. 3). The oxygendepletion system (ODS) provides an automatic shutoff mechanism whendecreased oxygen levels and resulting increased carbon monoxideconcentrations are detected. For example, the heater of the presentdesign is intended to automatically shut off at 100 PPM of carbonmonoxide at 18% oxygen levels (21% free normal air). A thermocouple 86monitors changes in temperature of the pilot flame which indicateschanges in oxygen and carbon monoxide levels. Previous designs found inthe prior art use a thermocouple/plunger type safety shut-offarrangement, which is not deemed to be as sophisticated or precise asthe ODS of the present invention. The addition of an ODS to portableunvented heaters is an improvement in the art and the first of its kind.A more detailed discussion of the ODS can be found in a variety ofresources.

The present invention significantly reduces the pressure from thepropane tank in one stage. The pilot burner must operate at 11″ watercolumn (W.C.) while the main burner may optionally operate at this samepressure although higher pressures are envisioned. This is the firstportable device for indoor use that the applicant is aware of thatconforms to this standard. The portable heaters that exist today alloperate at high pressures (on the order of 12 psi) and do notincorporate an ODS. In addition, the present device has the ability topass combustion requirements at a low fire condition.

In another embodiment of the invention illustrated in FIG. 15, the fuelsource is positioned within housing 10 and is accessible throughpivotable hinged door 100 with latch 102. Conical dome 52 extendspartway down vertical side 18 and over at least a portion of the valveof fuel supply 50. Pivotal movement of hinged door 100 is accomplishedby the user effecting vertical axial counterclockwise rotationalmovement about a pair of hinges or pivot axis (not shown) at one side ofthe door.

FIG. 17 illustrates yet another embodiment of the invention in whichimproved air flow is effected through heater unit A by the incorporationof a paddle or cage fan 110 in back panel 14. In one aspect shown inFIG. 16, a rechargeable battery pack 104 is illustrated to bepositionable within accommodating slot 116 within side panel 16 ofhousing 10. Knob 106 is used to variably define the power setting usedwith battery pack 104 as well as to be used as an “on/off’ switch forcontrolling the speed of fan 110. Alternatively, and in another aspectof the invention, at least one, preferably two or more rechargeable drycell batteries, 108 a, 108 b are employed within side panel 16 ofhousing 10 as better illustrated in FIG. 17. The batteries arepositioned to be loaded from the bottom of housing 10 and, the powercontrolled by a variably positioned knob 106 located toward the front ofhousing 10 or at an alternative position as is known in the art forcontrolling variable amounts of power to an electrical device. Dependingon the rotational speed of the fan desired, coupled with battery lifeexpectancy, anywhere from one to four “C” or “D” sized batteries areemployed, although it is equally envisioned that “AA” batteries may beused in some models where power consumption is envisioned to be minimalor usage infrequent and for short duration. Fan 110 has a plurality ofpaddles or inwardly extending panels for creating air movement throughrotational pivotal movement about axis 114. The fan is typically a lowervoltage fan, e.g., 3.0 volts, powered by a direct current motor. Thisincreased air flow insures maximal cooling capacity on various metal andplastic components in heater A. Battery operation is also illustrated inFIG. 26 where an alternative dry cell location is identified.

FIGS. 18-19 illustrate another embodiment of the invention in which asnap-fit door 100 is removable from side panel 18 thereby permittingpivotal rotational movement from a first position to a secondreplaceable position of fuel source 50 by a swivel connectionconfiguration. This configuration allows an end-user to rotate the fuelsource for easier canister replacement without having to simultaneouslylift the unit. This pivotal coupling is additionally illustrated in FIG.27 where one fuel source 50 is shown rotated approximately 90°. Rotationof fuel source 50 may be in any direction facilitating ease of access tofuel source 50, including towards the rear of heater A, as shown in FIG.19, or to the side of heater A, as shown in FIG. 26. Rotation in otherdirectionalities is also possible, including any directionality allowedby the physical shape and size of heater A. The predetermined angle thefuel source is able to rotate is not limited, and can be any angle thatfacilitates ease of replacing the fuel source, but will commonly beapproximately 90° from the heater, as shown in FIGS. 19 and 26, placingthe fully rotated fuel source on a horizontal plane, allowing the useraccess and allowing full uninhibited sight of the fuel source connectionto the heater.

As illustrated in FIG. 28, fuel source 50, typically propane cylinders,is secured to the rotational connection by a threading engagement withintank fitting 120 and is held in position by sheet metal bracket 117 withpivot axis. Tank fitting 120 connects fuel source 50 to swivel bodyreceiving connector 164, allowing the tanks to rotate to a predeterminedangle from the heater. The swivel body used to employ the swivelconnection will commonly determine the maximum angle the fuel source canrotate away from the heater, as rotation will be impeded by the designof the swivel body at a predetermined angle. Rotation ceases at receiverconnector 164, which connects to fitting nut 113. Tank fitting 120 willpreferably be rated to withstand a working pressure appropriate for thehigh pressure LP of the fuel source, typically approximately 150 psi.Commonly, at least one compression fitting is used to make theconnection between fuel source 50 and swivel body receiving connector164. FIGS. 28-33 illustrate fuel source 50 connected by tank fitting 120to swivel body receiving connector 164 when removed from the heater.

Within tank fitting 120 is a sealing system, made of at least one O-ring119 in one embodiment, so as to ensure a connection that will properlyseal when pressurized LP is run through the fitting and connection intoinlet fuel lines 115, leading into inline regulator 166. A check-valve(not shown) is located within tank fitting 120, or swivel body receivingconnector 164, to ensure a proper connection exists between fuel source50 and tank fitting 120. If the check-valve indicates a properconnection is not made, or a leak exists, fuel will not dispense intothe heater until the connection is corrected. The pressure of a checkvalve within tank fitting 120 also permits operation of the unit withonly one fuel source 50 attached.

Pivotal movement is effected by rotatable fuel supply connection 120feeding inlet fuel lines 115. Fuel lines 115 connect to singlestationary inline regulator 166, which reduces the delivery pressure ofthe fuel, as shown in FIG. 26. Inline regulator 166 is typically locatedwithin the housing in the previously unused space near the upper rearportion of the heater. Regulator 166 is not limited, however, to thislocation within the housing of the heater, and can be located in anyvolume within the housing as space permits, as long as regulator 166 isstationary. It is preferable that the regulator is centrally locatedwhen more than one fuel supply is used, as the fuel from both fuelsupplies run through the single inline regulator, however it is foreseenin one alternative embodiment that each fuel supply may use a separatestationary regulator. The position of the at least one regulator is onlylimited by the housing of the heater, and can be positioned on asubstantially vertical plane, a substantially horizontal plane, or canbe tilted on an angled plane, one example of which is shown in FIG. 34.In further embodiments of the heater, the stationary regulator may alsobe located exterior to the housing of the heater, and may be enclosed ina separate housing. Outlet fuel lines, such as outlet line 168 transportthe fuel from regulator 166 to valve and office 56 (shown in FIGS. 1-2).

FIGS. 20-27 illustrate yet another embodiment of the invention in whichmore than one fuel source is positionable within the housing. Asillustrated in FIG. 20, two fuel sources 50 a, 50 b are positionedwithin side wall 18 and at least partially covered by dome-shapedshoulders, and in one aspect, completely enclosed therein as illustratedin FIG. 21. Temperature controller button 20 and igniter button 22 arepositioned similarly to that shown previously in FIG. 4.

In FIGS. 22-23, two fuel sources 50 a, 50 b which are at least partiallyenclosed by dome-shaped side panels 52 a, 52 b are positioned on opposedsides 18, 16 of heater housing 10. In this particular embodiment, theunits are connected by a mixing valve (not shown) and the temperaturecontroller button 20 and igniter button 22 operate to control a singleburner unit.

In FIGS. 24-25, two fuel sources 50 a, 50 b are once again shown, thecanisters protruding at least partially from the rear 14 of heaterhousing 10. As illustrated in this embodiment, each fuel source has itsindividual temperature controller buttons 20 a, 20 b and igniter buttons22 a, 22 b for controlling the temperature of heater A.

It is recognized that when dual fuel source applications are discussed,it is recognized that the heat capacity of each burner need not be thesame, and it is within the scope of this invention that differentcapacity burners are envisioned. For maximum heat control by theend-user, it is within the scope of the invention that one burner willbe for “low” capacity applications and wherein the second burner will befor “high” capacity applications, and wherein the two burners can beused in combination to produce yet a higher capacity unit. For otherapplications, there will be two “low” capacity burners employed withinone unit as well as applications where there will be two “high” capacityburners employed within the same unit. Optionally, there areapplications wherein each burner (if each burner has a separate control)or a combined controller where each burner is commonly controlled) willhave an associated “low”, “medium” and “high” setting to permit stillfurther refinements in the heat provided by the device. Additionally, itis envisioned that the heating device will have a single controller andone burner, the controller/burner combination having “low”, “medium” and“high” settings. In a more expensive version of the heater, twocontinuously variable burners will be employed, such variabilitypredicated by the rate at which fuel and/or air is supplied to theburners as well as the capacity of the burners, although it isenvisioned that a single continuously variable burner is within thescope of this invention.

It should be noted that in embodiments of this invention in which morethan one fuel source is illustrated, that the fuel sources can either beoperated in tandem or individually. When operated in tandem, a mixingvalve is included prior to the burner. In some embodiments of theinvention, the second location of the fuel source is that of a storagecapacity only, and the unit operates as previously described. It shouldalso be noted that the handle 26 illustrated in many of the embodiments,is often optional, and that a heater which achieves portability by theincorporation of wheels 120 positioned at the bottom of the unit, betterillustrated in FIG. 27 is within the scope of this invention or whereinthe portability is associated with the incorporation of a wheeleddolly-like apparatus. When the wheels are of fairly small size, thenumber of wheels is at least three, preferably four and they arepivotable about a vertical axis. When the number is three, the wheelsare positioned in a triangular fashion with two wheels at opposed endson one side, and a third wheel in the middle of the unit on an opposedside. When the number is four, the wheels are positioned at the verticesof the base of the unit. In a specialized configuration, the number ofwheels can be reduced to two. When used in this manner, the wheels aremore similar to rollers and occupy at least 50% of the width of thebase, preferably more and extending essentially across a complete side,on both sides of the unit.

Alternative embodiments of the modes of attachment of the fuel supplyare illustrated in FIGS. 35-39. FIG. 35 illustrates an alternativeembodiment of the swivel connection showing slide channels 140, 142which contain sliding brackets 152 into which are positioned tankfitting 120 and swivel body 164. Flexible gas hose 148, associated tankfitting 146, inline regulator 150, and other hardware secureinterconnection between the fuel supply (not shown) and the burnerassembly. A convenient pull-tab 144 is optionally incorporated into eachbracket 152.

FIG. 36 illustrates yet another alternative embodiment to the swivel gasconnector in which swivel connection 119 swings out through its fixedpositioning within bracket 154 affixed to hinged 158 door assembly 100by bracket channel 156. In a manner similar to that described previouslywith FIG. 29, flexible gas hose 148 is used to interconnect between tankfitting (not shown) and inline regulator, which remains within thehousing of the heater, as opposed to swinging outwards with doorassembly 100, to secure interconnection between the fuel supply (notshown) and the burner assembly.

FIG. 37 illustrates yet a further alternative embodiment for theconvenience of removing the fuel supply and illustrates an arrangementwherein fuel source 50 with swivel connection 119 affixed thereto ispositionable within the housing by an inwardly biased resilient springclip 160 for fastening engagement about a middle of the fuel source anda second U-shaped bracket 162 fixedly attached to the heater housing forpositioning about a neck of the fuel source. In a manner similar to thatdescribed previously, flexible gas hose 148 is used to interconnectbetween inline regulator 146 (not shown) and gas line fitting (notshown) to secure interconnection between fuel supply 50 and the burnerassembly.

FIGS. 38 and 39 illustrate still yet a further alternative embodimentfor the locking of the swivel connection of the fuel source andillustrates an arrangement wherein swivel body 119 is additionallyequipped with rotating clip 172 with weight 174 positioned about aterminal edge. When the heater is in its up-right position 170 asillustrated in FIG. 38, clip 172 prohibits swivel body 119 fromrotating. When the heater is positioned on its back side, the clipswings back into a second position 178 due to the gravitational effectsupon weight 174 thereby swinging out of the way and allowing pivotalmovement of the tank for changing thereof. With the incorporation of aweighted clip, the rotating feature for tank installation and removal iseffected without changing the elevation of the tank as it moves from afirst angular position to a second angular position.

Therefore, what has been shown and illustrated is a portable heatingdevice in which the fuel source (typically at least one, and preferablytwo one pound cylinders) are moveable from a first use position into asecond position in which the fuel source is replaced. The at least onefuel source connects to a swivel body which connects to an associatedregulator (for decreasing the pressure of the exit port gas). This modeof operation in one embodiment is effected through the incorporation ofa braided gas hose which employs a sliding mechanism in which the userphysically pulls the cylinder from its use position inside the housing,to a replace position outside of the housing via telescoping or slidingmovement of rails. In a second embodiment, this mode of operation iseffected by the fixed incorporation of the swivel body into a door inthe housing within which is positioned the fuel source, therebyrequiring the user to open the door with cylinder attached forreplacement of the cylinder. In a third embodiment, this mode ofoperation is effected by removal of the fuel source from within thehousing which is attached by a clamp and bracket within the housingwhile in a fourth embodiment, this mode of operation is effected bypivotal movement of a swivel body within a pair of U-shaped clampshaving a pivot rod interposed therebetween. In yet a fifth embodiment,this mode of operation is effected by a swivel weighted clip whichrequires tilting of the heater prior to removal of the spent fuelcylinder.

In addition to the foregoing, a further application of theaforementioned heater encompasses the addition of a warming tray 200.Warming tray 200 is attached to the heater in any way to utilize theheat generated from the heater to warm items placed within the warmingtray 200, such as food or non-flammable articles.

FIGS. 40-44 show the heater having a warming tray 200 installedthereupon. Preferably, warming tray 200 is a non-flammable material,such as a sheet or metal grid, that is attached to the heater to allowarticles to be placed upon it. The warming tray 200 is able to supportthe articles thereupon. In more detail, the warming tray 200 is attachedat multiple points near the top of the heater and near the uppermostportion of the heater, namely, the outlet 92. Preferably, the warmingtray 200 has a tray portion 202 where the articles rest upon to bewarmed by the heater. The tray portion 202 is arranged perpendicular tothe heater, which is parallel to the ground upon which the heater rests.With reference to FIG. 40, Plane A is a plane running through the trayportion 202. Plane B is a plane running through the heater as shown inFIG. 40. Plane A and plane B are perpendicular to one another andfurther depict the orientation of the tray portion 202. Angular offsetsof the tray portion 202 from perpendicularity are within the scope ofthis invention. The tray portion 202 preferably extends above theuppermost portion of the housing of the heater. Other arrangements ofthe tray portion 202 are within the scope of this invention.

Tray portion 202 is supported by supporting means 204, which is also apart of the warming tray 200. Supporting means 204 are attached to thesheet or metal grid 30. Rear supporting means 206 are attached to, andwithin, the outlet 92. Warming tray 200 may also have (not shown) anenclosure to enclose articles placed upon/within it.

In the foregoing description, certain terms have been used for brevity,clearness and understanding; but no unnecessary limitations are to beimplied therefrom beyond the requirements of the prior art, because suchterms are used for descriptive purposes and are intended to be broadlyconstrued. Moreover, the description and illustration of the inventionis by way of example, and the scope of the invention is not limited tothe exact details shown or described.

This invention has been described in detail with reference to specificembodiments thereof, including the respective best modes for carryingout each embodiment. It shall be understood that these illustrations areby way of example and not by way of limitation.

Additionally, it will be apparent to those skilled in the art that theabove illustrative embodiments of the devices and methods mayincorporate changes and modifications without departing from the generalscope of this invention. It is intended to include all suchmodifications and alterations in so far as they come within the scope ofthe appended claims.

1. A portable radiant heater supplied by an associated fuel sourcecomprising: a housing having a handle for transporting the heater, saidhousing have a front and a rear portion wherein said front portion has ametal grid extending upon the front portion, the housing having a planethat extends through the center of the heater; a burner assembly havinga radiant surface that communicates with the plenum; and a warming trayhaving a tray portion, said tray portion attached to said front metalgrid for support, said tray portion having a plane which isperpendicular to the plane of said housing.